My Daughter Bella also was diagnosed at 4 years old right before kindergarten. This is a tough question to answer because every parent shares a different belief on sweets for their T1 kid. We decided just to let her have the cupcake because we didn’t want her to feel left out. What we did in order for her not to go way high was to check her sugar before hand, bolus 15 minutes before she has the cupcake and most of the time her sugars were fine after that. Also usually juice seemed to be the standard so we would pack her with a sugar free lemonade as well. If you have any other questions please let me know.